Mystery solenoid

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Supercharged111

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His year make and model are directly under the picture that he posted, no digging required.:33:

That requires me to rotate my phone.

OP did you trace the wiring all the way back? I'm wanting to use my factory isolator to charge 2 truck frame mounted camper batteries. I'm guessing, like others, that it was used either for that or maybe as a more significant source of power for your 7 way plug.
 

PlayingWithTBI

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I'm guessing, like others, that it was used either for that or maybe as a more significant source of power for your 7 way plug.
I have a Ford looking solenoid like that under the hood on my 88 C1500 that's not in use anymore. There was a toggle switch under the dash that actuated it. My guess is, since this was a farm truck in the Central Valley of California, the original owner had a bunch of lights mounted so he could work on balers or other equipment at night. I know he didn't use it for a plow :anitoof:
 

1998_K1500_Sub

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My 98 Suburban had a second battery added, on the driver's side later, and an "extra" relay was employed... a relay much like yours (except mine is located elsewhere).

In my case the purpose of the second battery was / is to provide power for battery operated appliances on a separate circuit in the Suburban, overnight.

The "extra" relay disconnects the second battery from the vehicle's main 12V circuit when the ignition is "off", and when "on" the second battery and the appliances on its separate circuit are charged / energized through the relay by the first battery and alternator.
 
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Darkimag22

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Thanks for the info guys. I have yet to trace the orange wire leading under the truck. I did remove the battery isolator the previous owner had installed (inner drivers side fender). Once my Cole Hersee smart battery isolator arrives, I am hoping I can fit in under the ecm blackbox. If there isn't room, it will go where the old isolator was mounted. Still have to come up with a game plan for a momentary switch installed in the cab to work with the boost function, too.
 

Supercharged111

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Thanks for the info guys. I have yet to trace the orange wire leading under the truck. I did remove the battery isolator the previous owner had installed (inner drivers side fender). Once my Cole Hersee smart battery isolator arrives, I am hoping I can fit in under the ecm blackbox. If there isn't room, it will go where the old isolator was mounted. Still have to come up with a game plan for a momentary switch installed in the cab to work with the boost function, too.

Orange wire you say? Does said orange wire dip into a factory harness? If so, PO may have opted to make the factory orange wire switched power instead of it being constant.
 

GMCTruck

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It looks like a typical setup for sending switched power to a 7 pole connector at the back of the truck for charging a trailer battery. Especially if it is an orange wire. The power probably came from one of the studs on the nearby fuse box. The trailer battery is only charged when the truck is running and so the truck battery is not drained when the truck is off. Usually this is used in a single battery setup. The mess to the right looks like two circuit breakers, possible one was for a trailer brake.
 

GoToGuy

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Sorry, if you don't have time to lead with what you need help with, it must not be important. Their all GMT 400 series, but it's 4 generations wthin that time frame. So I lead with year, now everbody knows where your starting. Like i said it doesn't cost you anything. You benefit from our technical advice. Some of us get paid for this, what does it cost you?
 

SS Performance

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It looks like a typical setup for sending switched power to a 7 pole connector at the back of the truck for charging a trailer battery. Especially if it is an orange wire. The power probably came from one of the studs on the nearby fuse box. The trailer battery is only charged when the truck is running and so the truck battery is not drained when the truck is off. Usually this is used in a single battery setup. The mess to the right looks like two circuit breakers, possible one was for a trailer brake.
I have a similar solenoid in my 96. It was used to supply 12vdc to the 7 pin trailer harness. It is wired so 12vdc is only supplied when the engine is running. I have never seen it on any other truck I have owned but it seems like a good idea.
 

Darkimag22

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Sorry, if you don't have time to lead with what you need help with, it must not be important. Their all GMT 400 series, but it's 4 generations wthin that time frame. So I lead with year, now everbody knows where your starting. Like i said it doesn't cost you anything. You benefit from our technical advice. Some of us get paid for this, what does it cost you?
Really??? I have all my truck info in my signature...did you maybe miss that? I am very aware about the different generations, engines, etc...this isn't my first rodeo bud. As I stated in my opening post, I was just curious if anyone had any ideas on what the extra solenoid was for before I ripped it out. But, hey, thanks for all your help....you get paid for being a dick on a truck forum...must be nice lmao.
 
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